Author: 798.eth

The bound platform, which has been quite popular in the Bitcoin ecosystem these days, was formerly known as radfi, a platform I started using at the end of 2025 due to a NodeStrategy monkey strategy token. Now it has upgraded and changed its name to bound exchange. This platform has a very special asset, which is actually the monkey strategy, a node monkey's flywheel, supported by underlying assets. The key is whether the underlying assets can hold up.

Today I mainly want to talk about its asset deposit and withdrawal logic and trading mechanisms. But before diving into the mechanisms, let me first explain the differences between the upgraded Bound and the original Radfi.

1. Previous and Current Life: From Radfi to Bound

Bound did not appear out of nowhere; it is the complete rewrite of radFi. The radFi official website now displays a line stating that radFi has evolved into bound.exchange. It is the same team, and the tech stack has shifted from Create-React-App to Next.js, a complete rewrite.

Bound has truly added a passkey built-in multi-chain wallet, Bitcoin collateralized lending of bUSD, and SODAX cross-chain. The trading engine is still radFi's concentrated liquidity AMM, with Runes swap unchanged.

This product line has two sets of 2-of-2 multi-signature with timelock. The account-level setup protects you; after three months, you can detach from Bound; the lending setup protects lenders, and once the grace period is over, lenders can directly take your collateral. (See the figure for a detailed item-by-item comparison between radFi and Bound).

2. Core Mechanism: Asset Deposit and Withdrawal with 2-of-2 Multi-signature Custody

Having understood its positioning, let's look at its asset management logic. There are mainly two points: first is 2-of-2 multi-signature custody, and second is the time lock (timelock) countdown protection in the event of platform theft or downtime.

Let’s set the scene. You have BTC, and you want to trade on a platform. The traditional method is to deposit coins into the platform’s wallet, and the platform holds them for you. The problem is that the coins are no longer in your hands; if the platform runs away or is compromised, your coins are gone, like FTX or Celsius. Bound aims to solve this contradiction: to have the transaction speed of a platform-level (CEX) while not giving up control of the coins.

Step 1: What is deposit?

After registering, Bound gives you a Bitcoin address that starts with bc1p. If you want to trade, you first need to transfer BTC from your own wallet to this address. A standard Bitcoin transfer takes about three confirmations, roughly half an hour. At this point, it is no different from using a regular wallet. The real design lies in the next question.

Step 2: Who holds the private key for this address?

This is the core of the entire system. There are only two clumsy methods: if the private key is only held by the platform, that’s custody, returning to the old problem of FTX; if the private key is only held by you, the platform cannot help you achieve rapid transactions, and you have to manually sign each trade, which is slow.

Bound's solution is that this address is not just assigned one key but two. To move the coins inside, both keys must sign. This is the 2-of-2 multi-signature.

Step 3: Who owns the two keys?

One key is yours, stored on your own device, called via passkey, and the private key never leaves the device. The other key is held on Bound's backend. During daily transactions, you sign with your passkey, and Bound's backend automatically supplies the other key, and with both together, transactions are completed in seconds.

Take a moment to grasp this step. Bound only has one key and cannot unilaterally move your coins, so it is not custodial and cannot take your coins for lending or borrowing. However, when the two come together, transactions can occur instantly, restoring the speed. This is the effect that 2-of-2 aims for: achieving both security and speed.

Step 4: What gap does the timelock fill?

The 2-of-2 brings a new problem. Since two keys are needed, if Bound runs away, crashes, or is shut down, the backend key is permanently inaccessible, leaving you with only one key; will the coins be locked in the address?

The timelock is there to fill this gap. The rule is simple: the multi-signature from Bound has a validity period of three months. Within these three months, two keys are required to move coins. After three months, your single key alone can withdraw all coins without needing Bound.

The key point is that this is not a promise made by Bound; it is written into the Bitcoin script and enforced by the Bitcoin network. Bound's agreement is irrelevant; once the time is up, you can sign and leave. This is the confidence behind its claim of self-custodial.

Step 5: Withdrawal is straightforward now.

For normal withdrawals, you sign with your passkey and Bound's backend signs collectively, and both keys are together, resulting in instant access. For an escape withdrawal, in case Bound is gone, you wait for the timelock to expire in three months, use your single signature, and send the coins to any address.

Looking at these five steps together, the first four terms form a chain: you deposit coins into a 2-of-2 address, which is deposit; during daily transactions, you use both keys with Bound to spend; Bound's key has a three-month expiration, which is the timelock; after the expiration, you can leave with just one key, which is the escape route for withdrawal.

3. Underlying Logic: Trading Order of Bound ex

Having understood how to deposit assets, let’s talk about the trading order of Bound ex.

There are no smart contracts on Bitcoin. So where does the AMM of Bitcoin's native DEX match your trades, and who decides the order of execution? Essentially, it is a CEX's matching backend, interfaced with the Bitcoin blockchain for settlement. Let's break it down step by step:

• First, the AMM curve is not on-chain. BTC L1 has no contracts, the states like reserves, ticks, and liquidity ranges have no place to be stored, so they can only be kept in Bound's backend database. The on-chain UTXOs are simply the results of holding and settling liquidity provider's funds.

• Second, on-chain transactions are only the settlement receipt. I pulled the transaction records from that pool, each transaction is a fixed amount written in stone, containing no curve calculations. The multiplication along the curve is completed in the backend before going on-chain. In a block with more than twenty transactions, each spends different UTXOs that do not connect to each other, exactly because the price was predetermined off-chain; going on-chain is merely recording a set of predetermined numbers.

• Third, how does a single transaction get a price? If you want to buy or sell at the front end, the front end needs to request a quote from the backend. The backend calculates based on the concentrated liquidity curve it maintains; your order consumes liquidity along the tick, deducting fees, and gives you a number. You sign a PSBT to fix this number, and once verified by the backend, it cooperatively broadcasts while pushing the curve one step. The curve only lives in the backend.

• Fourth, the order is dictated by this curve's mathematics, which cannot be circumvented. The curve has a state, and at any given moment, it only has one current position. Each incoming order consumes a portion of liquidity, pushing the curve to a new position, so the next order can only execute at this new position. This means that all orders cannot be settled simultaneously; they must be arranged in a strict sequence. The first order pushes the original position, then the second order pushes the new position, and so on.

• Fifth, but who determines the order and by what criteria is another matter. We must differentiate between two types of order: one is the real time when you click to confirm, and the other is the backend's actual processing order. Neither on-chain nor protocol guarantees that these two will align. Your order enters the queue in Bound's backend, whether it confirms it or not, if it processes based on arrival time or shifts someone's order forward or backward, it is entirely its internal matter, and you cannot see it.

• Sixth, this is where the operating party's MEV enters, sharper than ordinary on-chain MEV. Generally, DEX settling orders are at least placed in blocks, and post-analysis shows who rushed, who squeezed whom. Bound’s ordering happens off-chain, resulting in blocks leaving no marks of order; more than twenty transactions do not connect with one another on-chain. However, at the moment you confirm, the price has actually been calculated at a specific point along the curve. You just don’t know which position the order ranks in that block.

So Bound does not lack an order; the order must mathematically exist—all it does is gather the power to define that order into a black box. At the level of principal, it is indeed self-custodial with 2-of-2 and timelock, and the platform cannot move your coins, but the pricing of your transaction and its execution order are recorded entirely off-chain by them. Ultimately, this is just the matching backend of a CEX, connected to the largest blockchain in the world for settlement, with approximately ten minutes to finalize a block, which is irreversible once confirmed.

4. Practical Pitfalls and Experience Feedback

Finally, two practical details to avoid pitfalls. This 2-of-2 address only accepts BTC and Runes; sending BRC-20, Alkanes, or other chain tokens into it will result in permanent loss. Additionally, you can bypass the Bound setup and directly connect your own Unisat or Xverse, so you won't have 2-of-2 or timelock, and the coins remain in your single-signature wallet, at the cost of having to manually sign each transaction.

Currently, during the experience, there are still a few minor issues. I experimented and found that the previous transaction has already confirmed two blocks, but the Bound front end still shows pending, preventing me from placing the next trade. I hope the @Bound_Exchange officials can take a look at this issue.

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